Anderson was mayor of Hawthorne from 1940 to 1943 and a member of the California State Assembly from 1943 to 1950. He served as Lieutenant Governor of California from 1959 to 1967 but was defeated in a bid for a third term by Republican Robert Finch. During his office on August 13, 1965, he signed off on the orders to send 1,336 National Guard Troops into Los Angeles County, 48 hours after the Watts riots begun.

Anderson was first elected to the 91st Congress in 1968 and served 12 terms from 1969 to 1993. In Congress he became chair of the Committee on Public Works and Transportation. He decided not to run for re-election in 1992.